New Icosahedron style proof of concept

So I made an icosahedron out of BB ply. It involved a lot of sanding.

So, turns out sanding precisely is hard. I built a series of small boxes to hold the piece at the correct angles, and it got really close to good, and then I said “oh I’ll just clean it up a little freehand.” Bad plan.

Next time (if I do a next time) I’ll get more serious about sanding jigs to get it exact.

Still, as a proof of concept, this is kind of cool.


When faceting stones folks use a rig like this to swing the stone at a precise place and angle and to be certain not to bring it too far.

What you are doing is a bit different so you would have to make your own rig, but it would be clean and accurate. If you wander down that rabbit hole there is a similar much older design that diamond cutters used to use that would be easier to build but harder to use.


Very cool. After all that sanding I can still see two fingers.


Oh my! You do like pushing of envelopes! :grinning:


Nope no fingers. It was layered. I sliced a 1” tall icosahedron model into 1/8” layers in sketchup and cut them, with three registration holes for brass pins.

So this is solid ply. If you look closely you can see the three pins in one of the faces.

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Okay, one finger and a thumb… :wink:



Looks cool.

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I made a quick Blender of the older stone cutting tool layout. Different geometry backs (pentagon,hexagon, square, etc) and setting the height of the shelf to get the correct angle. They used dop wax to hold the stone in place but you might have a different method,

Sorry was posted in wrong thread origanally


So do you feel this technique has more potential than a hollow version with sanded fingers?

If you want your own wooden dice perhaps?

What’s wrong with hollow dice?

At six inches on a side perhaps but a half inch on a side not so much

Depends. Do you want gaps? There’s no real way to sand angled fingers down to have zero gaps. If you overshoot by even a tiny bit you’ll start to see space between the finger and the other face.

I was hoping for a truly solid wood icosahedron. I think it could be done but I have to find a more precise way to sand the angles and depth so that I get it just right.

I think if I upped the scale to be 2” I might be able to get a more accurate result.


Working up to it in grits on a horizontal disc sander would be the best way to go, but that’s not very practical for occasional use. Perhaps a palm sander clamped in a vise?

I think you could get very precise with the getup I sketched with the best point that the finished face will be more flat than just holding it could do.